Sun cap



FIG. 1 is a front perspective view of a sun cap showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side thereof;

FIG. 6 is a top view; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in the drawings illustrate stitching and form apart of the claimed design.

The ornamental design for a sun cap, as shown and described.